Please answer 7 8 and 9

In R [datarium package], the marketing dataset contains the impact of the amount of money spent on three advertising medias (youtube, facebook and newspaper) on sales. We want to build a model for estimating sales (y) based on the advertising budget invested in youtube (xl), facebook (x2) and newspaper (x3). Use the output provided to answer the questions below. After some trial and error, the following model was fit: youtube + facebook + newspaper, data = marketing) > model summary(model) Call: Im(formula = sales youtube + facebook + newspaper, data = marketing) ICULUU Min -10.5932 1Q -1.0690 Median 0.2902 3Q 1.4272 Max 3.3951 Coefficients: Estimate Std. Error t value Pr(>ltl) (Intercept) 3.526667 0.374290 9.422 model2 summary(model2) Call: Im(formula = sales youtube + facebook + youtube: facebook, data = marketing) Residuals: Min 1Q Median -7.6039 -0.4833 0.2197 3Q Max 0.7137 1.8295 Coefficients: Estimate Std. Error t value Pr(>ltl) (Intercept) 8.100e+00 2.974e-01 27.233